1. Field of Invention
The present invention relates to a semiconductor manufacturing device and a method. More particularly, the present invention relates to a device and method for planarizing a film layer.
2. Description of Related Art
As semiconductor manufacturing passes into the deep submicron scale, dimensions of each device shrink. Hence, a higher operating speed for each integrated circuit results. For an integrated circuit with the same device layout, operating speed is closely related to density of the devices.
One major problem often encountered in metal plug fabrication, damascene processes or the deposition of a layer of dielectric material between neighboring lines or devices is the gap-filling capability of the material involved. Following the reduction of device dimensions and width of circuit lines, device density increases. In the process of filling the gaps or trenches on a silicon wafer, voids may be formed especially when the gaps or trenches are smaller than 0.1 .mu.m.
FIG. 1 is a schematic, cross-sectional view after forming an inter-layer dielectric (ILD) layer over a substrate that has circuit lines thereon in a multi-level metallization process. As shown in FIG. 1, metal lines 110 are formed on a substrate 100 so that there is a gap 120 between two neighboring metal lines 110. A dielectric layer 130 is formed over the substrate and the metal lines 110. Due to the poor gap-filling capability of the deposited dielectric material when the dielectric layer 130 is formed, a void 140 is likely to form within the dielectric layer 130 inside the gap region 120. The void 140 not only can lead to poor insulation, but can also enclose some corrosive chemicals that can corrode the metallic lines 110 and result in circuit problems. In addition, too much topographical height difference H after the deposition of the dielectric layer 130 is likely to affect subsequent photolithographic and etching processes as well. This is because only a highly planar surface can avoid the problems due to light diffusion during exposure so that a clear pattern is transferred.